1. Field of the Invention
This invention relates to fiber optic image transmitting devices and more particularly to means for enhancing optical images emitted thereby.
2. Description of the Prior Art
Bundles of optical fibers having their corresponding opposite ends arranged in identical geometrical patterns afford image transmitters which conduct image forming light by the well known principles of total internal reflection. The packing tightness and particular mosaic patterning of the fiber ends, their respective diameters and cladding thickness as well as absence or existence of broken fiber cores individually and collectively affect the image resolving power of the bundles whether they are of the rigid or intermediately flexible (fiberscope) type. In particular, the image degrading effects of broken fibers and transmission variations between fibers becomes accumulative in fiberscopes of extra long lengths especially when end-to-end coupling of two or more fiber bundles is necessary to satisfy a length requirement.
As evidence of the recognition in the art that spacings between light-conducting cores and defects of fiber breakage, foreign matter inclusions and the like are at least to some extent inevitable, dynamic image enhancement schemes have been devised to integrate the mosaic patterning of fiber ends and non-conducting or partially conducting spaces resulting from fiber breakage and/or transmission variations between fibers.
The theory of dynamic scanning is explained in the Journal of the Optical Society of America, Vol. 47, No. 5, May, 1957, pages. 423-427 and also in the New York Academic Press, 1967, pages. 88-99. Heretofore, however, dynamic scanning has not had practical application in fiber optic industrial or medical endoscopy. The ungainliness complexity and costliness of prior art applications of dynamic scanning have for the most part outweighed and/or defeated their advantages. U.S. Pat. No. 3,016,785 is exemplary. Its complex and ungainly mechanism for effecting a break-up motion between opposite ends of a fiber bundle and optical images received and emitted thereby is not utilitarian in fiber optic endoscopes which must not be so distally or otherwise encumbered.
Simiarly, U.S. Pat. Nos. 3,217,588 and 3,217,589 synchronously nutate images at the receiving and output ends of fiber optic cables using motor driven geared mechanisms which are bulky and heavy, complex and costly and limited to use in areas other than those of industrial inspection or medical examining endoscopy where unencumbered instrumentation is required.
An object of the invention is to provide an image enhancement system for industrial and medical fiberscopes which is of simple construction, inexpensive and uniquely compact.
A further object is to accomplish high resolution of image and blemish suppression in industrial inspection and medical examining fiberscopes without encumberance of the fiberscope structure or function.
Other objects and advantages of the invention will become apparent from the following description.